1030 lines
35 KiB
Plaintext
1030 lines
35 KiB
Plaintext
=head1 NAME
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perldelta - what's new for perl5.005
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=head1 DESCRIPTION
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This document describes differences between the 5.004 release and this one.
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=head1 About the new versioning system
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Perl is now developed on two tracks: a maintenance track that makes
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small, safe updates to released production versions with emphasis on
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compatibility; and a development track that pursues more aggressive
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evolution. Maintenance releases (which should be considered production
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quality) have subversion numbers that run from C<1> to C<49>, and
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development releases (which should be considered "alpha" quality) run
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from C<50> to C<99>.
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Perl 5.005 is the combined product of the new dual-track development
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scheme.
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=head1 Incompatible Changes
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=head2 WARNING: This version is not binary compatible with Perl 5.004.
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Starting with Perl 5.004_50 there were many deep and far-reaching changes
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to the language internals. If you have dynamically loaded extensions
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that you built under perl 5.003 or 5.004, you can continue to use them
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with 5.004, but you will need to rebuild and reinstall those extensions
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to use them 5.005. See L<INSTALL> for detailed instructions on how to
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upgrade.
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=head2 Default installation structure has changed
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The new Configure defaults are designed to allow a smooth upgrade from
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5.004 to 5.005, but you should read L<INSTALL> for a detailed
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discussion of the changes in order to adapt them to your system.
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=head2 Perl Source Compatibility
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When none of the experimental features are enabled, there should be
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very few user-visible Perl source compatibility issues.
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If threads are enabled, then some caveats apply. C<@_> and C<$_> become
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lexical variables. The effect of this should be largely transparent to
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the user, but there are some boundary conditions under which user will
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need to be aware of the issues. For example, C<local(@_)> results in
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a "Can't localize lexical variable @_ ..." message. This may be enabled
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in a future version.
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Some new keywords have been introduced. These are generally expected to
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have very little impact on compatibility. See L<New C<INIT> keyword>,
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L<New C<lock> keyword>, and L<New C<qr//> operator>.
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Certain barewords are now reserved. Use of these will provoke a warning
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if you have asked for them with the C<-w> switch.
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See L<C<our> is now a reserved word>.
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=head2 C Source Compatibility
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There have been a large number of changes in the internals to support
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the new features in this release.
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=over 4
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=item Core sources now require ANSI C compiler
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An ANSI C compiler is now B<required> to build perl. See F<INSTALL>.
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=item All Perl global variables must now be referenced with an explicit prefix
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All Perl global variables that are visible for use by extensions now
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have a C<PL_> prefix. New extensions should C<not> refer to perl globals
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by their unqualified names. To preserve sanity, we provide limited
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backward compatibility for globals that are being widely used like
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C<sv_undef> and C<na> (which should now be written as C<PL_sv_undef>,
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C<PL_na> etc.)
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If you find that your XS extension does not compile anymore because a
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perl global is not visible, try adding a C<PL_> prefix to the global
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and rebuild.
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It is strongly recommended that all functions in the Perl API that don't
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begin with C<perl> be referenced with a C<Perl_> prefix. The bare function
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names without the C<Perl_> prefix are supported with macros, but this
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support may cease in a future release.
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See L<perlguts/"API LISTING">.
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=item Enabling threads has source compatibility issues
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Perl built with threading enabled requires extensions to use the new
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C<dTHR> macro to initialize the handle to access per-thread data.
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If you see a compiler error that talks about the variable C<thr> not
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being declared (when building a module that has XS code), you need
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to add C<dTHR;> at the beginning of the block that elicited the error.
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The API function C<perl_get_sv("@",FALSE)> should be used instead of
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directly accessing perl globals as C<GvSV(errgv)>. The API call is
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backward compatible with existing perls and provides source compatibility
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with threading is enabled.
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See L<"C Source Compatibility"> for more information.
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=back
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=head2 Binary Compatibility
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This version is NOT binary compatible with older versions. All extensions
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will need to be recompiled. Further binaries built with threads enabled
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are incompatible with binaries built without. This should largely be
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transparent to the user, as all binary incompatible configurations have
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their own unique architecture name, and extension binaries get installed at
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unique locations. This allows coexistence of several configurations in
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the same directory hierarchy. See F<INSTALL>.
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=head2 Security fixes may affect compatibility
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A few taint leaks and taint omissions have been corrected. This may lead
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to "failure" of scripts that used to work with older versions. Compiling
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with -DINCOMPLETE_TAINTS provides a perl with minimal amounts of changes
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to the tainting behavior. But note that the resulting perl will have
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known insecurities.
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Oneliners with the C<-e> switch do not create temporary files anymore.
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=head2 Relaxed new mandatory warnings introduced in 5.004
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Many new warnings that were introduced in 5.004 have been made
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optional. Some of these warnings are still present, but perl's new
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features make them less often a problem. See L<New Diagnostics>.
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=head2 Licensing
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Perl has a new Social Contract for contributors. See F<Porting/Contract>.
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The license included in much of the Perl documentation has changed.
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Most of the Perl documentation was previously under the implicit GNU
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General Public License or the Artistic License (at the user's choice).
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Now much of the documentation unambigously states the terms under which
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it may be distributed. Those terms are in general much less restrictive
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than the GNU GPL. See L<perl> and the individual perl man pages listed
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therein.
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=head1 Core Changes
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=head2 Threads
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WARNING: Threading is considered an B<experimental> feature. Details of the
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implementation may change without notice. There are known limitations
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and some bugs. These are expected to be fixed in future versions.
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See L<README.threads>.
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Mach cthreads (NEXTSTEP, OPENSTEP, Rhapsody) are now supported by
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the Thread extension.
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=head2 Compiler
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WARNING: The Compiler and related tools are considered B<experimental>.
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Features may change without notice, and there are known limitations
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and bugs. Since the compiler is fully external to perl, the default
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configuration will build and install it.
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The Compiler produces three different types of transformations of a
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perl program. The C backend generates C code that captures perl's state
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just before execution begins. It eliminates the compile-time overheads
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of the regular perl interpreter, but the run-time performance remains
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comparatively the same. The CC backend generates optimized C code
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equivalent to the code path at run-time. The CC backend has greater
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potential for big optimizations, but only a few optimizations are
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implemented currently. The Bytecode backend generates a platform
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independent bytecode representation of the interpreter's state
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just before execution. Thus, the Bytecode back end also eliminates
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much of the compilation overhead of the interpreter.
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The compiler comes with several valuable utilities.
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C<B::Lint> is an experimental module to detect and warn about suspicious
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code, especially the cases that the C<-w> switch does not detect.
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C<B::Deparse> can be used to demystify perl code, and understand
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how perl optimizes certain constructs.
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C<B::Xref> generates cross reference reports of all definition and use
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of variables, subroutines and formats in a program.
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C<B::Showlex> show the lexical variables used by a subroutine or file
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at a glance.
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C<perlcc> is a simple frontend for compiling perl.
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See C<ext/B/README>, L<B>, and the respective compiler modules.
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=head2 Regular Expressions
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Perl's regular expression engine has been seriously overhauled, and
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many new constructs are supported. Several bugs have been fixed.
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Here is an itemized summary:
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=over 4
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=item Many new and improved optimizations
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Changes in the RE engine:
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Unneeded nodes removed;
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Substrings merged together;
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New types of nodes to process (SUBEXPR)* and similar expressions
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quickly, used if the SUBEXPR has no side effects and matches
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strings of the same length;
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Better optimizations by lookup for constant substrings;
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Better search for constants substrings anchored by $ ;
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Changes in Perl code using RE engine:
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More optimizations to s/longer/short/;
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study() was not working;
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/blah/ may be optimized to an analogue of index() if $& $` $' not seen;
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Unneeded copying of matched-against string removed;
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Only matched part of the string is copying if $` $' were not seen;
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=item Many bug fixes
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Note that only the major bug fixes are listed here. See F<Changes> for others.
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Backtracking might not restore start of $3.
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No feedback if max count for * or + on "complex" subexpression
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was reached, similarly (but at compile time) for {3,34567}
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Primitive restrictions on max count introduced to decrease a
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possibility of a segfault;
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(ZERO-LENGTH)* could segfault;
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(ZERO-LENGTH)* was prohibited;
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Long REs were not allowed;
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/RE/g could skip matches at the same position after a
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zero-length match;
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=item New regular expression constructs
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The following new syntax elements are supported:
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(?<=RE)
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(?<!RE)
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(?{ CODE })
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(?i-x)
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(?i:RE)
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(?(COND)YES_RE|NO_RE)
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(?>RE)
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\z
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=item New operator for precompiled regular expressions
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See L<New C<qr//> operator>.
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=item Other improvements
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Better debugging output (possibly with colors),
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even from non-debugging Perl;
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RE engine code now looks like C, not like assembler;
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Behaviour of RE modifiable by `use re' directive;
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Improved documentation;
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Test suite significantly extended;
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Syntax [:^upper:] etc., reserved inside character classes;
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=item Incompatible changes
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(?i) localized inside enclosing group;
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$( is not interpolated into RE any more;
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/RE/g may match at the same position (with non-zero length)
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after a zero-length match (bug fix).
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=back
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See L<perlre> and L<perlop>.
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=head2 Improved malloc()
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See banner at the beginning of C<malloc.c> for details.
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=head2 Quicksort is internally implemented
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Perl now contains its own highly optimized qsort() routine. The new qsort()
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is resistant to inconsistent comparison functions, so Perl's C<sort()> will
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not provoke coredumps any more when given poorly written sort subroutines.
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(Some C library C<qsort()>s that were being used before used to have this
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problem.) In our testing, the new C<qsort()> required the minimal number
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of pair-wise compares on average, among all known C<qsort()> implementations.
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See C<perlfunc/sort>.
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=head2 Reliable signals
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Perl's signal handling is susceptible to random crashes, because signals
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arrive asynchronously, and the Perl runtime is not reentrant at arbitrary
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times.
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However, one experimental implementation of reliable signals is available
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when threads are enabled. See C<Thread::Signal>. Also see F<INSTALL> for
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how to build a Perl capable of threads.
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=head2 Reliable stack pointers
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The internals now reallocate the perl stack only at predictable times.
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In particular, magic calls never trigger reallocations of the stack,
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because all reentrancy of the runtime is handled using a "stack of stacks".
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This should improve reliability of cached stack pointers in the internals
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and in XSUBs.
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=head2 More generous treatment of carriage returns
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Perl used to complain if it encountered literal carriage returns in
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scripts. Now they are mostly treated like whitespace within program text.
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Inside string literals and here documents, literal carriage returns are
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ignored if they occur paired with linefeeds, or get interpreted as whitespace
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if they stand alone. This behavior means that literal carriage returns
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in files should be avoided. You can get the older, more compatible (but
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less generous) behavior by defining the preprocessor symbol
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C<PERL_STRICT_CR> when building perl. Of course, all this has nothing
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whatever to do with how escapes like C<\r> are handled within strings.
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Note that this doesn't somehow magically allow you to keep all text files
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in DOS format. The generous treatment only applies to files that perl
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itself parses. If your C compiler doesn't allow carriage returns in
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files, you may still be unable to build modules that need a C compiler.
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=head2 Memory leaks
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C<substr>, C<pos> and C<vec> don't leak memory anymore when used in lvalue
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context. Many small leaks that impacted applications that embed multiple
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interpreters have been fixed.
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=head2 Better support for multiple interpreters
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The build-time option C<-DMULTIPLICITY> has had many of the details
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reworked. Some previously global variables that should have been
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per-interpreter now are. With care, this allows interpreters to call
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each other. See the C<PerlInterp> extension on CPAN.
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=head2 Behavior of local() on array and hash elements is now well-defined
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See L<perlsub/"Temporary Values via local()">.
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=head2 C<%!> is transparently tied to the L<Errno> module
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See L<perlvar>, and L<Errno>.
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=head2 Pseudo-hashes are supported
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See L<perlref>.
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=head2 C<EXPR foreach EXPR> is supported
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See L<perlsyn>.
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=head2 Keywords can be globally overridden
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See L<perlsub>.
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=head2 C<$^E> is meaningful on Win32
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See L<perlvar>.
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=head2 C<foreach (1..1000000)> optimized
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C<foreach (1..1000000)> is now optimized into a counting loop. It does
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not try to allocate a 1000000-size list anymore.
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=head2 C<Foo::> can be used as implicitly quoted package name
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Barewords caused unintuitive behavior when a subroutine with the same
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name as a package happened to be defined. Thus, C<new Foo @args>,
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use the result of the call to C<Foo()> instead of C<Foo> being treated
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as a literal. The recommended way to write barewords in the indirect
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object slot is C<new Foo:: @args>. Note that the method C<new()> is
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called with a first argument of C<Foo>, not C<Foo::> when you do that.
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=head2 C<exists $Foo::{Bar::}> tests existence of a package
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It was impossible to test for the existence of a package without
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actually creating it before. Now C<exists $Foo::{Bar::}> can be
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used to test if the C<Foo::Bar> namespace has been created.
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=head2 Better locale support
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See L<perllocale>.
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=head2 Experimental support for 64-bit platforms
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Perl5 has always had 64-bit support on systems with 64-bit longs.
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Starting with 5.005, the beginnings of experimental support for systems
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with 32-bit long and 64-bit 'long long' integers has been added.
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If you add -DUSE_LONG_LONG to your ccflags in config.sh (or manually
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define it in perl.h) then perl will be built with 'long long' support.
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There will be many compiler warnings, and the resultant perl may not
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work on all systems. There are many other issues related to
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third-party extensions and libraries. This option exists to allow
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people to work on those issues.
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=head2 prototype() returns useful results on builtins
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See L<perlfunc/prototype>.
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=head2 Extended support for exception handling
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C<die()> now accepts a reference value, and C<$@> gets set to that
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value in exception traps. This makes it possible to propagate
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exception objects. This is an undocumented B<experimental> feature.
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=head2 Re-blessing in DESTROY() supported for chaining DESTROY() methods
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See L<perlobj/Destructors>.
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=head2 All C<printf> format conversions are handled internally
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See L<perlfunc/printf>.
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=head2 New C<INIT> keyword
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C<INIT> subs are like C<BEGIN> and C<END>, but they get run just before
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the perl runtime begins execution. e.g., the Perl Compiler makes use of
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C<INIT> blocks to initialize and resolve pointers to XSUBs.
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=head2 New C<lock> keyword
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The C<lock> keyword is the fundamental synchronization primitive
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in threaded perl. When threads are not enabled, it is currently a noop.
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To minimize impact on source compatibility this keyword is "weak", i.e., any
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user-defined subroutine of the same name overrides it, unless a C<use Thread>
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has been seen.
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=head2 New C<qr//> operator
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The C<qr//> operator, which is syntactically similar to the other quote-like
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operators, is used to create precompiled regular expressions. This compiled
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form can now be explicitly passed around in variables, and interpolated in
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other regular expressions. See L<perlop>.
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=head2 C<our> is now a reserved word
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Calling a subroutine with the name C<our> will now provoke a warning when
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using the C<-w> switch.
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=head2 Tied arrays are now fully supported
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See L<Tie::Array>.
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=head2 Tied handles support is better
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Several missing hooks have been added. There is also a new base class for
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TIEARRAY implementations. See L<Tie::Array>.
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=head2 4th argument to substr
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substr() can now both return and replace in one operation. The optional
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4th argument is the replacement string. See L<perlfunc/substr>.
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=head2 Negative LENGTH argument to splice
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splice() with a negative LENGTH argument now work similar to what the
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LENGTH did for substr(). Previously a negative LENGTH was treated as
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0. See L<perlfunc/splice>.
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=head2 Magic lvalues are now more magical
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When you say something like C<substr($x, 5) = "hi">, the scalar returned
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by substr() is special, in that any modifications to it affect $x.
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(This is called a 'magic lvalue' because an 'lvalue' is something on
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the left side of an assignment.) Normally, this is exactly what you
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would expect to happen, but Perl uses the same magic if you use substr(),
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pos(), or vec() in a context where they might be modified, like taking
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a reference with C<\> or as an argument to a sub that modifies C<@_>.
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In previous versions, this 'magic' only went one way, but now changes
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to the scalar the magic refers to ($x in the above example) affect the
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magic lvalue too. For instance, this code now acts differently:
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$x = "hello";
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sub printit {
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$x = "g'bye";
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print $_[0], "\n";
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}
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printit(substr($x, 0, 5));
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In previous versions, this would print "hello", but it now prints "g'bye".
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=head2 E<lt>E<gt> now reads in records
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If C<$/> is a referenence to an integer, or a scalar that holds an integer,
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E<lt>E<gt> will read in records instead of lines. For more info, see
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L<perlvar/$/>.
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=head2 pack() format 'Z' supported
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The new format type 'Z' is useful for packing and unpacking null-terminated
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strings. See L<perlfunc/"pack">.
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=head1 Significant bug fixes
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=head2 E<lt>HANDLEE<gt> on empty files
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With C<$/> set to C<undef>, slurping an empty file returns a string of
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zero length (instead of C<undef>, as it used to) for the first time the
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HANDLE is read. Subsequent reads yield C<undef>.
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This means that the following will append "foo" to an empty file (it used
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to not do anything before):
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perl -0777 -pi -e 's/^/foo/' empty_file
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|
Note that the behavior of:
|
|
|
|
perl -pi -e 's/^/foo/' empty_file
|
|
|
|
is unchanged (it continues to leave the file empty).
|
|
|
|
=head1 Supported Platforms
|
|
|
|
Configure has many incremental improvements. Site-wide policy for building
|
|
perl can now be made persistent, via Policy.sh. Configure also records
|
|
the command-line arguments used in F<config.sh>.
|
|
|
|
=head2 New Platforms
|
|
|
|
BeOS is now supported. See L<README.beos>.
|
|
|
|
DOS is now supported under the DJGPP tools. See L<README.dos>.
|
|
|
|
GNU/Hurd is now supported.
|
|
|
|
MiNT is now supported. See L<README.mint>.
|
|
|
|
MPE/iX is now supported. See L<README.mpeix>.
|
|
|
|
MVS (aka OS390, aka Open Edition) is now supported. See L<README.os390>.
|
|
|
|
Stratus VOS is now supported. See L<README.vos>.
|
|
|
|
=head2 Changes in existing support
|
|
|
|
Win32 support has been vastly enhanced. Support for Perl Object, a C++
|
|
encapsulation of Perl. GCC and EGCS are now supported on Win32.
|
|
See F<README.win32>, aka L<perlwin32>.
|
|
|
|
VMS configuration system has been rewritten. See L<README.vms>.
|
|
|
|
The hints files for most Unix platforms have seen incremental improvements.
|
|
|
|
=head1 Modules and Pragmata
|
|
|
|
=head2 New Modules
|
|
|
|
=over
|
|
|
|
=item B
|
|
|
|
Perl compiler and tools. See L<B>.
|
|
|
|
=item Data::Dumper
|
|
|
|
A module to pretty print Perl data. See L<Data::Dumper>.
|
|
|
|
=item Dumpvalue
|
|
|
|
A module to dump perl values to the screen. See L<Dumpvalue>.
|
|
|
|
=item Errno
|
|
|
|
A module to look up errors more conveniently. See L<Errno>.
|
|
|
|
=item File::Spec
|
|
|
|
A portable API for file operations.
|
|
|
|
=item ExtUtils::Installed
|
|
|
|
Query and manage installed modules.
|
|
|
|
=item ExtUtils::Packlist
|
|
|
|
Manipulate .packlist files.
|
|
|
|
=item Fatal
|
|
|
|
Make functions/builtins succeed or die.
|
|
|
|
=item IPC::SysV
|
|
|
|
Constants and other support infrastructure for System V IPC operations
|
|
in perl.
|
|
|
|
=item Test
|
|
|
|
A framework for writing testsuites.
|
|
|
|
=item Tie::Array
|
|
|
|
Base class for tied arrays.
|
|
|
|
=item Tie::Handle
|
|
|
|
Base class for tied handles.
|
|
|
|
=item Thread
|
|
|
|
Perl thread creation, manipulation, and support.
|
|
|
|
=item attrs
|
|
|
|
Set subroutine attributes.
|
|
|
|
=item fields
|
|
|
|
Compile-time class fields.
|
|
|
|
=item re
|
|
|
|
Various pragmata to control behavior of regular expressions.
|
|
|
|
=back
|
|
|
|
=head2 Changes in existing modules
|
|
|
|
=over
|
|
|
|
=item Benchmark
|
|
|
|
You can now run tests for I<n> seconds instead of guessing the right
|
|
number of tests to run: e.g. timethese(-5, ...) will run each of the
|
|
codes for at least 5 CPU seconds. Zero as the "number of repetitions"
|
|
means "for at least 3 CPU seconds". The output format has also
|
|
changed. For example:
|
|
|
|
use Benchmark;$x=3;timethese(-5,{a=>sub{$x*$x},b=>sub{$x**2}})
|
|
|
|
will now output something like this:
|
|
|
|
Benchmark: running a, b, each for at least 5 CPU seconds...
|
|
a: 5 wallclock secs ( 5.77 usr + 0.00 sys = 5.77 CPU) @ 200551.91/s (n=1156516)
|
|
b: 4 wallclock secs ( 5.00 usr + 0.02 sys = 5.02 CPU) @ 159605.18/s (n=800686)
|
|
|
|
New features: "each for at least N CPU seconds...", "wallclock secs",
|
|
and the "@ operations/CPU second (n=operations)".
|
|
|
|
=item Carp
|
|
|
|
Carp has a new function cluck(). cluck() warns, like carp(), but also adds
|
|
a stack backtrace to the error message, like confess().
|
|
|
|
=item CGI
|
|
|
|
CGI has been updated to version 2.42.
|
|
|
|
=item Fcntl
|
|
|
|
More Fcntl constants added: F_SETLK64, F_SETLKW64, O_LARGEFILE for
|
|
large (more than 4G) file access (the 64-bit support is not yet
|
|
working, though, so no need to get overly excited), Free/Net/OpenBSD
|
|
locking behaviour flags F_FLOCK, F_POSIX, Linux F_SHLCK, and
|
|
O_ACCMODE: the mask of O_RDONLY, O_WRONLY, and O_RDWR.
|
|
|
|
=item Math::Complex
|
|
|
|
The accessor methods Re, Im, arg, abs, rho, and theta, can now also
|
|
act as mutators (accessor $z->Re(), mutator $z->Re(3)).
|
|
|
|
=item Math::Trig
|
|
|
|
A little bit of radial trigonometry (cylindrical and spherical) added:
|
|
radial coordinate conversions and the great circle distance.
|
|
|
|
=item POSIX
|
|
|
|
POSIX now has its own platform-specific hints files.
|
|
|
|
=item DB_File
|
|
|
|
DB_File supports version 2.x of Berkeley DB. See C<ext/DB_File/Changes>.
|
|
|
|
=item MakeMaker
|
|
|
|
MakeMaker now supports writing empty makefiles, provides a way to
|
|
specify that site umask() policy should be honored. There is also
|
|
better support for manipulation of .packlist files, and getting
|
|
information about installed modules.
|
|
|
|
Extensions that have both architecture-dependent and
|
|
architecture-independent files are now always installed completely in
|
|
the architecture-dependent locations. Previously, the shareable parts
|
|
were shared both across architectures and across perl versions and were
|
|
therefore liable to be overwritten with newer versions that might have
|
|
subtle incompatibilities.
|
|
|
|
=item CPAN
|
|
|
|
See <perlmodinstall> and L<CPAN>.
|
|
|
|
=item Cwd
|
|
|
|
Cwd::cwd is faster on most platforms.
|
|
|
|
=item Benchmark
|
|
|
|
Keeps better time.
|
|
|
|
=back
|
|
|
|
=head1 Utility Changes
|
|
|
|
C<h2ph> and related utilities have been vastly overhauled.
|
|
|
|
C<perlcc>, a new experimental front end for the compiler is available.
|
|
|
|
The crude GNU C<configure> emulator is now called C<configure.gnu> to
|
|
avoid trampling on C<Configure> under case-insensitive filesystems.
|
|
|
|
C<perldoc> used to be rather slow. The slower features are now optional.
|
|
In particular, case-insensitive searches need the C<-i> switch, and
|
|
recursive searches need C<-r>. You can set these switches in the
|
|
C<PERLDOC> environment variable to get the old behavior.
|
|
|
|
=head1 Documentation Changes
|
|
|
|
Config.pm now has a glossary of variables.
|
|
|
|
F<Porting/patching.pod> has detailed instructions on how to create and
|
|
submit patches for perl.
|
|
|
|
L<perlport> specifies guidelines on how to write portably.
|
|
|
|
L<perlmodinstall> describes how to fetch and install modules from C<CPAN>
|
|
sites.
|
|
|
|
Some more Perl traps are documented now. See L<perltrap>.
|
|
|
|
L<perlopentut> gives a tutorial on using open().
|
|
|
|
L<perlreftut> gives a tutorial on references.
|
|
|
|
L<perlthrtut> gives a tutorial on threads.
|
|
|
|
=head1 New Diagnostics
|
|
|
|
=over
|
|
|
|
=item Ambiguous call resolved as CORE::%s(), qualify as such or use &
|
|
|
|
(W) A subroutine you have declared has the same name as a Perl keyword,
|
|
and you have used the name without qualification for calling one or the
|
|
other. Perl decided to call the builtin because the subroutine is
|
|
not imported.
|
|
|
|
To force interpretation as a subroutine call, either put an ampersand
|
|
before the subroutine name, or qualify the name with its package.
|
|
Alternatively, you can import the subroutine (or pretend that it's
|
|
imported with the C<use subs> pragma).
|
|
|
|
To silently interpret it as the Perl operator, use the C<CORE::> prefix
|
|
on the operator (e.g. C<CORE::log($x)>) or by declaring the subroutine
|
|
to be an object method (see L<attrs>).
|
|
|
|
=item Bad index while coercing array into hash
|
|
|
|
(F) The index looked up in the hash found as the 0'th element of a
|
|
pseudo-hash is not legal. Index values must be at 1 or greater.
|
|
See L<perlref>.
|
|
|
|
=item Bareword "%s" refers to nonexistent package
|
|
|
|
(W) You used a qualified bareword of the form C<Foo::>, but
|
|
the compiler saw no other uses of that namespace before that point.
|
|
Perhaps you need to predeclare a package?
|
|
|
|
=item Can't call method "%s" on an undefined value
|
|
|
|
(F) You used the syntax of a method call, but the slot filled by the
|
|
object reference or package name contains an undefined value.
|
|
Something like this will reproduce the error:
|
|
|
|
$BADREF = 42;
|
|
process $BADREF 1,2,3;
|
|
$BADREF->process(1,2,3);
|
|
|
|
=item Can't check filesystem of script "%s" for nosuid
|
|
|
|
(P) For some reason you can't check the filesystem of the script for nosuid.
|
|
|
|
=item Can't coerce array into hash
|
|
|
|
(F) You used an array where a hash was expected, but the array has no
|
|
information on how to map from keys to array indices. You can do that
|
|
only with arrays that have a hash reference at index 0.
|
|
|
|
=item Can't goto subroutine from an eval-string
|
|
|
|
(F) The "goto subroutine" call can't be used to jump out of an eval "string".
|
|
(You can use it to jump out of an eval {BLOCK}, but you probably don't want to.)
|
|
|
|
=item Can't localize pseudo-hash element
|
|
|
|
(F) You said something like C<local $ar-E<gt>{'key'}>, where $ar is
|
|
a reference to a pseudo-hash. That hasn't been implemented yet, but
|
|
you can get a similar effect by localizing the corresponding array
|
|
element directly -- C<local $ar-E<gt>[$ar-E<gt>[0]{'key'}]>.
|
|
|
|
=item Can't use %%! because Errno.pm is not available
|
|
|
|
(F) The first time the %! hash is used, perl automatically loads the
|
|
Errno.pm module. The Errno module is expected to tie the %! hash to
|
|
provide symbolic names for C<$!> errno values.
|
|
|
|
=item Cannot find an opnumber for "%s"
|
|
|
|
(F) A string of a form C<CORE::word> was given to prototype(), but
|
|
there is no builtin with the name C<word>.
|
|
|
|
=item Character class syntax [. .] is reserved for future extensions
|
|
|
|
(W) Within regular expression character classes ([]) the syntax beginning
|
|
with "[." and ending with ".]" is reserved for future extensions.
|
|
If you need to represent those character sequences inside a regular
|
|
expression character class, just quote the square brackets with the
|
|
backslash: "\[." and ".\]".
|
|
|
|
=item Character class syntax [: :] is reserved for future extensions
|
|
|
|
(W) Within regular expression character classes ([]) the syntax beginning
|
|
with "[:" and ending with ":]" is reserved for future extensions.
|
|
If you need to represent those character sequences inside a regular
|
|
expression character class, just quote the square brackets with the
|
|
backslash: "\[:" and ":\]".
|
|
|
|
=item Character class syntax [= =] is reserved for future extensions
|
|
|
|
(W) Within regular expression character classes ([]) the syntax
|
|
beginning with "[=" and ending with "=]" is reserved for future extensions.
|
|
If you need to represent those character sequences inside a regular
|
|
expression character class, just quote the square brackets with the
|
|
backslash: "\[=" and "=\]".
|
|
|
|
=item %s: Eval-group in insecure regular expression
|
|
|
|
(F) Perl detected tainted data when trying to compile a regular expression
|
|
that contains the C<(?{ ... })> zero-width assertion, which is unsafe.
|
|
See L<perlre/(?{ code })>, and L<perlsec>.
|
|
|
|
=item %s: Eval-group not allowed, use re 'eval'
|
|
|
|
(F) A regular expression contained the C<(?{ ... })> zero-width assertion,
|
|
but that construct is only allowed when the C<use re 'eval'> pragma is
|
|
in effect. See L<perlre/(?{ code })>.
|
|
|
|
=item %s: Eval-group not allowed at run time
|
|
|
|
(F) Perl tried to compile a regular expression containing the C<(?{ ... })>
|
|
zero-width assertion at run time, as it would when the pattern contains
|
|
interpolated values. Since that is a security risk, it is not allowed.
|
|
If you insist, you may still do this by explicitly building the pattern
|
|
from an interpolated string at run time and using that in an eval().
|
|
See L<perlre/(?{ code })>.
|
|
|
|
=item Explicit blessing to '' (assuming package main)
|
|
|
|
(W) You are blessing a reference to a zero length string. This has
|
|
the effect of blessing the reference into the package main. This is
|
|
usually not what you want. Consider providing a default target
|
|
package, e.g. bless($ref, $p || 'MyPackage');
|
|
|
|
=item Illegal hex digit ignored
|
|
|
|
(W) You may have tried to use a character other than 0 - 9 or A - F in a
|
|
hexadecimal number. Interpretation of the hexadecimal number stopped
|
|
before the illegal character.
|
|
|
|
=item No such array field
|
|
|
|
(F) You tried to access an array as a hash, but the field name used is
|
|
not defined. The hash at index 0 should map all valid field names to
|
|
array indices for that to work.
|
|
|
|
=item No such field "%s" in variable %s of type %s
|
|
|
|
(F) You tried to access a field of a typed variable where the type
|
|
does not know about the field name. The field names are looked up in
|
|
the %FIELDS hash in the type package at compile time. The %FIELDS hash
|
|
is usually set up with the 'fields' pragma.
|
|
|
|
=item Out of memory during ridiculously large request
|
|
|
|
(F) You can't allocate more than 2^31+"small amount" bytes. This error
|
|
is most likely to be caused by a typo in the Perl program. e.g., C<$arr[time]>
|
|
instead of C<$arr[$time]>.
|
|
|
|
=item Range iterator outside integer range
|
|
|
|
(F) One (or both) of the numeric arguments to the range operator ".."
|
|
are outside the range which can be represented by integers internally.
|
|
One possible workaround is to force Perl to use magical string
|
|
increment by prepending "0" to your numbers.
|
|
|
|
=item Recursive inheritance detected while looking for method '%s' in package '%s'
|
|
|
|
(F) More than 100 levels of inheritance were encountered while invoking a
|
|
method. Probably indicates an unintended loop in your inheritance hierarchy.
|
|
|
|
=item Reference found where even-sized list expected
|
|
|
|
(W) You gave a single reference where Perl was expecting a list with
|
|
an even number of elements (for assignment to a hash). This
|
|
usually means that you used the anon hash constructor when you meant
|
|
to use parens. In any case, a hash requires key/value B<pairs>.
|
|
|
|
%hash = { one => 1, two => 2, }; # WRONG
|
|
%hash = [ qw/ an anon array / ]; # WRONG
|
|
%hash = ( one => 1, two => 2, ); # right
|
|
%hash = qw( one 1 two 2 ); # also fine
|
|
|
|
=item Undefined value assigned to typeglob
|
|
|
|
(W) An undefined value was assigned to a typeglob, a la C<*foo = undef>.
|
|
This does nothing. It's possible that you really mean C<undef *foo>.
|
|
|
|
=item Use of reserved word "%s" is deprecated
|
|
|
|
(D) The indicated bareword is a reserved word. Future versions of perl
|
|
may use it as a keyword, so you're better off either explicitly quoting
|
|
the word in a manner appropriate for its context of use, or using a
|
|
different name altogether. The warning can be suppressed for subroutine
|
|
names by either adding a C<&> prefix, or using a package qualifier,
|
|
e.g. C<&our()>, or C<Foo::our()>.
|
|
|
|
=item perl: warning: Setting locale failed.
|
|
|
|
(S) The whole warning message will look something like:
|
|
|
|
perl: warning: Setting locale failed.
|
|
perl: warning: Please check that your locale settings:
|
|
LC_ALL = "En_US",
|
|
LANG = (unset)
|
|
are supported and installed on your system.
|
|
perl: warning: Falling back to the standard locale ("C").
|
|
|
|
Exactly what were the failed locale settings varies. In the above the
|
|
settings were that the LC_ALL was "En_US" and the LANG had no value.
|
|
This error means that Perl detected that you and/or your system
|
|
administrator have set up the so-called variable system but Perl could
|
|
not use those settings. This was not dead serious, fortunately: there
|
|
is a "default locale" called "C" that Perl can and will use, the
|
|
script will be run. Before you really fix the problem, however, you
|
|
will get the same error message each time you run Perl. How to really
|
|
fix the problem can be found in L<perllocale/"LOCALE PROBLEMS">.
|
|
|
|
=back
|
|
|
|
|
|
=head1 Obsolete Diagnostics
|
|
|
|
=over
|
|
|
|
=item Can't mktemp()
|
|
|
|
(F) The mktemp() routine failed for some reason while trying to process
|
|
a B<-e> switch. Maybe your /tmp partition is full, or clobbered.
|
|
|
|
Removed because B<-e> doesn't use temporary files any more.
|
|
|
|
=item Can't write to temp file for B<-e>: %s
|
|
|
|
(F) The write routine failed for some reason while trying to process
|
|
a B<-e> switch. Maybe your /tmp partition is full, or clobbered.
|
|
|
|
Removed because B<-e> doesn't use temporary files any more.
|
|
|
|
=item Cannot open temporary file
|
|
|
|
(F) The create routine failed for some reason while trying to process
|
|
a B<-e> switch. Maybe your /tmp partition is full, or clobbered.
|
|
|
|
Removed because B<-e> doesn't use temporary files any more.
|
|
|
|
=item regexp too big
|
|
|
|
(F) The current implementation of regular expressions uses shorts as
|
|
address offsets within a string. Unfortunately this means that if
|
|
the regular expression compiles to longer than 32767, it'll blow up.
|
|
Usually when you want a regular expression this big, there is a better
|
|
way to do it with multiple statements. See L<perlre>.
|
|
|
|
=back
|
|
|
|
=head1 Configuration Changes
|
|
|
|
You can use "Configure -Uinstallusrbinperl" which causes installperl
|
|
to skip installing perl also as /usr/bin/perl. This is useful if you
|
|
prefer not to modify /usr/bin for some reason or another but harmful
|
|
because many scripts assume to find Perl in /usr/bin/perl.
|
|
|
|
=head1 BUGS
|
|
|
|
If you find what you think is a bug, you might check the headers of
|
|
recently posted articles in the comp.lang.perl.misc newsgroup.
|
|
There may also be information at http://www.perl.com/perl/, the Perl
|
|
Home Page.
|
|
|
|
If you believe you have an unreported bug, please run the B<perlbug>
|
|
program included with your release. Make sure you trim your bug down
|
|
to a tiny but sufficient test case. Your bug report, along with the
|
|
output of C<perl -V>, will be sent off to <F<perlbug@perl.com>> to be
|
|
analysed by the Perl porting team.
|
|
|
|
=head1 SEE ALSO
|
|
|
|
The F<Changes> file for exhaustive details on what changed.
|
|
|
|
The F<INSTALL> file for how to build Perl.
|
|
|
|
The F<README> file for general stuff.
|
|
|
|
The F<Artistic> and F<Copying> files for copyright information.
|
|
|
|
=head1 HISTORY
|
|
|
|
Written by Gurusamy Sarathy <F<gsar@umich.edu>>, with many contributions
|
|
from The Perl Porters.
|
|
|
|
Send omissions or corrections to <F<perlbug@perl.com>>.
|
|
|
|
=cut
|